Betterment is a great option if you want an automated, low-fee portfolio from the largest independent provider of digital accounts. Betterment was a pioneer in providing "set-it-and-forget-it" portfolios for a low-fee.
Consider TD Essentials if you want an automated portfolio and you have an existing banking or brokerage relationship with TD Ameritrade.
Betterment
Automated
TD Ameritrade
Automated